Extending the range of a wifi network

[#1]

Recommendation wanted for a wireless router (or alternative)
I'd like to extend the area covered by a wireless router (possibly buy a new router), my workshop has an apartment above it (granny flat) that SWMBO want to use as a temporary office
I’m currently using a netgear DG834G which does not appear to have a strong enough signal, I’ve tried Ethernet mains extenders which do not appear to work beyond the fuse box. I’d like to run wifi into my workshop (50 meters away....through 2 x 2'6" solid walls).
Am open to any suggestions.

[#2]

You could try a new antenna http://www.broadbandbuyer.co.uk/Shop/ShopSearch.asp?CategoryID=32
A new router probably wouldn't solve your issues

[#3]

I would try mounting a wireless-N ACCESS POINT in the highest and nearest window (on the house side), using your mains extenders to get your network from your existing router up to the ethernet connector on the access point.
Then on the granny flat side, I would used a wireless-N BRIDGE, in the highest and nearest window (to the house), then connect your network stuff to the bridge's ethernet sockets.
Wireless-N should have enough range to do what you want, especially if the link is between two facing windows.
If you can find wireless-N kit that runs on 5GHz instead of the more usual 2.4GHz, then that would leave all your existing wireless-G channels still available.

[#4]

Increase Wireless Router Range with Tinfoil
http://www.fixmyowncomputer.com/2007/10/increase-wireless-router-range-with-tinfoil/

[#5]

I have a Netgear ANT2405 booster attached to my router. If you enter that in Google several links come up. It's a rather old (about 5years) piece of technology but I've just done a quick Google and it appears to be still available, at around the £20 mark. It comes with a lead which replaces the aerial rod on the router and a box about the size of two matchboxes and a mounting plate which you fit as high up in the room as possible. Using this I get a virtually full signal showing on my wife's laptop anywhere in the house, and also a usable strength signal in our summerhouise about 20 metres up the garden. When helping our next door neighbour (two detached houses) with his bb connection, I noticed his computer showed a usable connection to my router. Needless to say he doesn't have my WPA protected password!

[#6]

Another option might be:
Edimax EW-7209APg Access Point/ Range Extender http://www.edimax.co.uk/en/produce_detail.php?pd_id=19&pl1_id=1&pl2_id=5
and
Edimax EA-IO7D 7dBi Antenna http://www.edimax.co.uk/en/product_search.php
(I am using an EW-7209APg to connect my Foxsat Satellite Box to my Router so that I can watch the iPlayer on my TV).

[#7]

I have had success with the Edimax wireless range extenders.  But you must make sure Netgear DG834G is set to use a fixed wireless channel (rather than automatically selecting the channel) because if the Netgear changes its wireless channel, the Edimax (or AFAIK any other wireless range extender) cannot follow the change.